I. Field of the Invention
The present invention relates to a fuel fill nozzle for automotive vehicles.
II. Description of Related Art
Essentially all automotive vehicles include a fuel fill tube assembly having a lower end open to the interior of a fuel tank and its upper end accessible exteriorly of the vehicle. Conventionally, the upper or inlet end of the fill tube assembly is sealingly closed by a fuel cap or other closure during normal operation of the vehicle. This fuel cap or other closure, of course, is removed from the fill tube assembly during a fueling operation.
The previously known fill tube assemblies typically comprised an elongated tubular and cylindrical main body having its lower end open to the interior of the fuel tank. Conversely, the upper end of the main body is joined to an enlarged diameter portion to which the fuel cap is removably secured. During a fueling operation, a gasoline fill nozzle is insertable through the enlarged diameter inlet portion so that a free end of the gasoline fill nozzle is positioned within the interior of the main body.
In order to prevent, or at least minimize, the introduction of leaded or diesel fuel into the fuel tank, the unleaded gasoline version of these previously known fill tube assemblies have conventionally included a normally closed flapper valve within the enlarged diameter inlet portion of the fill tube assembly. Conventionally, these flapper valves include a baffle which extends diametrically across the inlet portion of the fill tube assembly. An opening is provided through the baffle which is dimensioned to receive the fill nozzle. A spring loaded normally closed valve assembly is then mounted to the baffle to close the baffle opening at all times except during a fueling operation. During a fueling operation, the fuel nozzle is inserted through the baffle opening thus opening the valve.
In order to physically accommodate the valve structure of the flapper valve within the inlet portion of the fill tube assembly, it has been previously necessary that the baffle opening be radially offset from the center of the baffle. The radially offset opening in the baffle has, in turn, required that the axis of the main portion of the fill tube assembly be radially offset from the inlet portion of the fill tube assembly to ensure that the free end of the gasoline fill nozzle enters into the interior of the main body of the fill tube assembly during a fueling operation, while the gasoline fill nozzle is latched securely within the inlet portion.
A primary disadvantage of these previously known fill tube assemblies in which the axis of the main body is radially offset from the axis of the inlet portion of the fill tube assembly is that such a construction for the fill tube assembly is relatively expensive in manufacturing cost. Furthermore, since the main body and inlet portion are typically of a one-piece construction, the previously known fill tube assemblies in which the axis of the main body is radially offset from the axis of the inlet portion of the fill tube assembly can result in areas of weakening of the fill tube assembly where the enlarged diameter inlet portion is mechanically expanded from a smaller diameter tube.
The present invention provides a fill tube assembly which overcomes all of the above-mentioned disadvantages of the previously known devices.
In brief, the fill tube assembly of the present invention comprises a fill tube having a tubular and cylindrical main body with a predetermined inside diameter. The fill tube further includes an enlarged diameter inlet portion joined at one end to one end of the main body. This inlet portion, furthermore, has a predetermined diameter greater than the diameter of the main body.
The main body and inlet portion are preferably of a one-piece construction and are coaxial with each other. As such, the main body and inlet portion may be relatively inexpensively constructed.
The inlet portion is dimensioned so that a gas fill nozzle is insertable through the inlet portion and, after insertion to a latched position, a free end of the fill nozzle is positioned within the interior of the main body. Additionally, the diameter of the main body is configured so that, upon fuel flow from the gas nozzle into the interior of the main body, a liquid seal is formed by the fuel flow from the gasoline fill nozzle with the main body. This liquid seal, in operation, entrains any fuel fumes that are present within the fill tube with some outside air and the incoming fuel so that the incoming fuel, together with the entrained air and fuel fumes, enters into the fuel tank. If desired, check valves may be coupled in series with the fill tube at or adjacent the fuel tank.